. "Catalysis of the reaction: 2 6,7-dimethyl-8-(1-D-ribityl)lumazine + H(+) = 5-amino-6-(D-ribitylamino)uracil + riboflavin." . . "riboflavin synthase activity" . "lumazine synthase activity" . "6,7-dimethyl-8-(1-D-ribityl)lumazine:6,7-dimethyl-8-(1-D-ribityl)lumazine 2,3-butanediyltransferase activity" . "heavy riboflavin synthase" . "light riboflavin synthase" . "riboflavin synthetase activity" . "riboflavine synthase activity" . "riboflavine synthetase activity" . "vitamin B2 synthase activity" . . .